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            MySQL入门---数据库登陆与退出、数据库基本操作、开启数据库服务 | 
        
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        <ol class="post-toc"><li class="post-toc-item post-toc-level-1"><a class="post-toc-link" href="#开启和关闭服务"><span class="post-toc-number">1.</span> <span class="post-toc-text">开启和关闭服务</span></a></li><li class="post-toc-item post-toc-level-1"><a class="post-toc-link" href="#登陆"><span class="post-toc-number">2.</span> <span class="post-toc-text">登陆</span></a></li><li class="post-toc-item post-toc-level-1"><a class="post-toc-link" href="#退出"><span class="post-toc-number">3.</span> <span class="post-toc-text">退出</span></a></li><li class="post-toc-item post-toc-level-1"><a class="post-toc-link" href="#修改MySQL提示符"><span class="post-toc-number">4.</span> <span class="post-toc-text">修改MySQL提示符</span></a><ol class="post-toc-child"><li class="post-toc-item post-toc-level-2"><a class="post-toc-link" href="#登陆时指定"><span class="post-toc-number">4.1.</span> <span class="post-toc-text">登陆时指定</span></a></li><li class="post-toc-item post-toc-level-2"><a class="post-toc-link" href="#登陆后指定"><span class="post-toc-number">4.2.</span> <span class="post-toc-text">登陆后指定</span></a></li></ol></li><li class="post-toc-item post-toc-level-1"><a class="post-toc-link" href="#常用命令"><span class="post-toc-number">5.</span> <span class="post-toc-text">常用命令</span></a></li><li class="post-toc-item post-toc-level-1"><a class="post-toc-link" href="#语句规范"><span class="post-toc-number">6.</span> <span class="post-toc-text">语句规范</span></a></li><li class="post-toc-item post-toc-level-1"><a class="post-toc-link" href="#基本操作"><span class="post-toc-number">7.</span> <span class="post-toc-text">基本操作</span></a><ol class="post-toc-child"><li class="post-toc-item post-toc-level-2"><a class="post-toc-link" href="#创建数据库"><span class="post-toc-number">7.1.</span> <span class="post-toc-text">创建数据库</span></a></li><li class="post-toc-item post-toc-level-2"><a class="post-toc-link" href="#显示数据库"><span class="post-toc-number">7.2.</span> <span class="post-toc-text">显示数据库</span></a><ol class="post-toc-child"><li class="post-toc-item post-toc-level-3"><a class="post-toc-link" href="#显示WARNINGS"><span class="post-toc-number">7.2.1.</span> <span class="post-toc-text">显示WARNINGS</span></a></li></ol></li><li class="post-toc-item post-toc-level-2"><a class="post-toc-link" href="#显示创建数据库的指令（查看数据库信息）"><span class="post-toc-number">7.3.</span> <span class="post-toc-text">显示创建数据库的指令（查看数据库信息）</span></a></li><li class="post-toc-item post-toc-level-2"><a class="post-toc-link" href="#修改数据库"><span class="post-toc-number">7.4.</span> <span class="post-toc-text">修改数据库</span></a></li><li class="post-toc-item post-toc-level-2"><a class="post-toc-link" href="#删除数据库"><span class="post-toc-number">7.5.</span> <span class="post-toc-text">删除数据库</span></a></li></ol></li></ol>

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                MySQL入门---数据库登陆与退出、数据库基本操作、开启数据库服务
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        <strong>wangchao</strong>
        <span>7月 03, 2017</span>
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        <h1 id="开启和关闭服务"><a href="#开启和关闭服务" class="headerlink" title="开启和关闭服务"></a>开启和关闭服务</h1><ul>
<li>net start mysql 启动服务</li>
<li>net stop mysql 停止服务<a id="more"></a>
执行此命令前，需要安装服务：<blockquote>
<p>mysqld -install </p>
</blockquote>
</li>
</ul>
<p>服务的名称往往不是mysql，而是mysql加上版本号，例如mysql57</p>
<h1 id="登陆"><a href="#登陆" class="headerlink" title="登陆"></a>登陆</h1><p>登陆使用mysql命令，该命令有以下参数：</p>
<table>
<thead>
<tr>
<th style="text-align:center">参数</th>
<th style="text-align:center">作用</th>
</tr>
</thead>
<tbody>
<tr>
<td style="text-align:center">-D</td>
<td style="text-align:center">打开指定数据库</td>
</tr>
<tr>
<td style="text-align:center">–delimiter=name</td>
<td style="text-align:center">指定分隔符</td>
</tr>
<tr>
<td style="text-align:center">-h(–host=name)</td>
<td style="text-align:center">服务器名称(如果是默认的localhost，可以不写该选项)</td>
</tr>
<tr>
<td style="text-align:center">-p(小写)(–password[=password])</td>
<td style="text-align:center">输入密码</td>
</tr>
<tr>
<td style="text-align:center">-P(大写)(–port)</td>
<td style="text-align:center">端口号（如果是默认3306端口可以不写该选项）</td>
</tr>
<tr>
<td style="text-align:center">-u(–user=name)</td>
<td style="text-align:center">用户名</td>
</tr>
<tr>
<td style="text-align:center">-V(大写)（–version）</td>
<td style="text-align:center">获得版本</td>
</tr>
</tbody>
</table>
<h1 id="退出"><a href="#退出" class="headerlink" title="退出"></a>退出</h1><p>三个命令作用相同：</p>
<ul>
<li>exit </li>
<li>quit </li>
<li>\q </li>
</ul>
<h1 id="修改MySQL提示符"><a href="#修改MySQL提示符" class="headerlink" title="修改MySQL提示符"></a>修改MySQL提示符</h1><h2 id="登陆时指定"><a href="#登陆时指定" class="headerlink" title="登陆时指定"></a>登陆时指定</h2><p>可以在登陆时用–prompt指定提示符<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div></pre></td><td class="code"><pre><div class="line">C:\Users\twilight&gt;mysql -uroot -p123456 --prompt \u@\h-\d</div></pre></td></tr></table></figure></p>
<h2 id="登陆后指定"><a href="#登陆后指定" class="headerlink" title="登陆后指定"></a>登陆后指定</h2><p>用<strong> prompt </strong>命令<br>常用的参数：</p>
<ul>
<li>\D 完整的日期</li>
<li>\d 当前数据库</li>
<li>\h 服务器名称</li>
<li>\u 当前用户</li>
</ul>
<p>因为当前没有选择数据库，所以\d 显示none<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div></pre></td><td class="code"><pre><div class="line">mysql&gt;prompt \u@\h \d</div><div class="line">root@localhost (none)</div><div class="line">root@localhost (none)use student</div><div class="line">Database changed</div><div class="line">root@localhost student</div><div class="line">root@localhost student prompt \u@\h-\d \D：</div><div class="line">PROMPT set to &apos;prompt \u@\h-\d \D：&apos;</div><div class="line">prompt root@localhost-student Fri Jun 30 10:42:56 2017：</div></pre></td></tr></table></figure></p>
<h1 id="常用命令"><a href="#常用命令" class="headerlink" title="常用命令"></a>常用命令</h1><ul>
<li>select version();显示当前服务器版本号</li>
<li>select now();  显示当前日期时间</li>
<li>select user(); 显示当前用户</li>
</ul>
<h1 id="语句规范"><a href="#语句规范" class="headerlink" title="语句规范"></a>语句规范</h1><ul>
<li>关键字与函数名称全部大写</li>
<li>数据库名、表名称、字段名称全部小写</li>
<li>sql语句必须以分号结尾</li>
</ul>
<h1 id="基本操作"><a href="#基本操作" class="headerlink" title="基本操作"></a>基本操作</h1><h2 id="创建数据库"><a href="#创建数据库" class="headerlink" title="创建数据库"></a>创建数据库</h2><p><strong>CREATE {DATABASE | SHEMAS} [IF NOT EXISTS] db_name [DEFAULT] CHARACTER SET [=] charset_set_name</strong></p>
<p>直接创建<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line">mysql&gt; CREATE DATABASE test;</div><div class="line">Query OK, 1 row affected (0.00 sec)</div></pre></td></tr></table></figure></p>
<p>创建时指定编码方式：<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line">mysql&gt; CREATE DATABASE test2 CHARACTER SET GBK;</div><div class="line">Query OK, 1 row affected (0.00 sec)</div></pre></td></tr></table></figure></p>
<p>使用IF NOT EXISTS判断数据库是否已存在：<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line">mysql&gt; CREATE DATABASE IF NOT EXISTS test;</div><div class="line">Query OK, 1 row affected, 1 warning (0.00 sec)</div></pre></td></tr></table></figure></p>
<h2 id="显示数据库"><a href="#显示数据库" class="headerlink" title="显示数据库"></a>显示数据库</h2><p><strong>SHOW {DATABASES | SCHEMAS} [LIKE ‘pattern’ | WHERE expr]</strong><br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div></pre></td><td class="code"><pre><div class="line">mysql&gt; SHOW DATABASES;</div><div class="line">+--------------------+</div><div class="line">| Database           |</div><div class="line">+--------------------+</div><div class="line">| information_schema |</div><div class="line">| mysql              |</div><div class="line">| performance_schema |</div><div class="line">| sakila             |</div><div class="line">| student            |</div><div class="line">| sys                |</div><div class="line">| test               |</div><div class="line">| test2              |</div><div class="line">| world              |</div><div class="line">+--------------------+</div><div class="line">9 rows in set (0.00 sec)</div></pre></td></tr></table></figure></p>
<h3 id="显示WARNINGS"><a href="#显示WARNINGS" class="headerlink" title="显示WARNINGS"></a>显示WARNINGS</h3><p><strong>SHOW WARNINGS</strong><br>产生WARNINGS时查看警告的具体信息：<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div></pre></td><td class="code"><pre><div class="line">mysql&gt; SHOW WARNINGS;</div><div class="line">+-------+------+-----------------------------------------------+</div><div class="line">| Level | Code | Message                                       |</div><div class="line">+-------+------+-----------------------------------------------+</div><div class="line">| Note  | 1007 | Can&apos;t create database &apos;test&apos;; database exists |</div><div class="line">+-------+------+-----------------------------------------------+</div><div class="line">1 row in set (0.00 sec)</div></pre></td></tr></table></figure></p>
<h2 id="显示创建数据库的指令（查看数据库信息）"><a href="#显示创建数据库的指令（查看数据库信息）" class="headerlink" title="显示创建数据库的指令（查看数据库信息）"></a>显示创建数据库的指令（查看数据库信息）</h2><p><strong>SHOW CREATE DATABASE NAEM</strong></p>
<p>用该命令可以查看数据库的信息，比如，该数据库的编码方式是gbk<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div></pre></td><td class="code"><pre><div class="line">mysql&gt; SHOW CREATE DATABASE test2;</div><div class="line">+----------+---------------------------------------------------------------+</div><div class="line">| Database | Create Database                                               |</div><div class="line">+----------+---------------------------------------------------------------+</div><div class="line">| test2    | CREATE DATABASE `test2` /*!40100 DEFAULT CHARACTER SET gbk */ |</div><div class="line">+----------+---------------------------------------------------------------+</div><div class="line">1 row in set (0.00 sec)</div></pre></td></tr></table></figure></p>
<h2 id="修改数据库"><a href="#修改数据库" class="headerlink" title="修改数据库"></a>修改数据库</h2><p><strong>ALTER {DATABASE | SCHEMA}[db_name] [DEFAULT] CHARACTER SET [=] charset_name </strong></p>
<p>使用alter修改数据库的默认编码方式：<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div></pre></td><td class="code"><pre><div class="line">mysql&gt; ALTER DATABASE test2 CHARACTER SET UTF8;</div><div class="line">Query OK, 1 row affected (0.00 sec)</div></pre></td></tr></table></figure></p>
<p>查看修改后的编码,已经变成了utf-8：<br><figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div></pre></td><td class="code"><pre><div class="line">mysql&gt; SHOW CREATE DATABASE test2;</div><div class="line">+----------+----------------------------------------------------------------+</div><div class="line">| Database | Create Database                                                |</div><div class="line">+----------+----------------------------------------------------------------+</div><div class="line">| test2    | CREATE DATABASE `test2` /*!40100 DEFAULT CHARACTER SET utf8 */ |</div><div class="line">+----------+----------------------------------------------------------------+</div><div class="line">1 row in set (0.00 sec)</div></pre></td></tr></table></figure></p>
<h2 id="删除数据库"><a href="#删除数据库" class="headerlink" title="删除数据库"></a>删除数据库</h2><p><strong>DROP {DATABASE | SCHEMA} [IF EXISTS] db_name</strong></p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><div class="line">1</div><div class="line">2</div><div class="line">3</div><div class="line">4</div><div class="line">5</div><div class="line">6</div><div class="line">7</div><div class="line">8</div><div class="line">9</div><div class="line">10</div><div class="line">11</div><div class="line">12</div><div class="line">13</div><div class="line">14</div><div class="line">15</div><div class="line">16</div><div class="line">17</div></pre></td><td class="code"><pre><div class="line">mysql&gt; DROP DATABASE test2;</div><div class="line">Query OK, 0 rows affected (0.01 sec)</div><div class="line"></div><div class="line">mysql&gt; SHOW DATABASES;</div><div class="line">+--------------------+</div><div class="line">| Database           |</div><div class="line">+--------------------+</div><div class="line">| information_schema |</div><div class="line">| mysql              |</div><div class="line">| performance_schema |</div><div class="line">| sakila             |</div><div class="line">| student            |</div><div class="line">| sys                |</div><div class="line">| test               |</div><div class="line">| world              |</div><div class="line">+--------------------+</div><div class="line">8 rows in set (0.00 sec)</div></pre></td></tr></table></figure>

    

    
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